/*
  Example: spline interpolation
  using spline/seval (spline.cpp)
  AG: February 2007
*/
#include <iostream>
#include <iomanip>
#include <cmath>
#include "spline.cpp"

using namespace std;

double spline (double[], double[], double[], double[], double[], int);
double seval  (double[], double[], double[], double[], double[], int, double);

int main ()
{
    const int n = 11;
    int i;
    double x[n] = {-1.0,-0.8,-0.6,-0.4,-0.2,0.0,0.2,0.4,0.6,0.8,1.0};
    double y[n] = {0.0385,0.0588,0.1,0.2,0.5,1.0,0.5,0.2,0.1,0.0588,0.0385};
    double b[n], c[n], d[n];
    double u, s;

    cout.setf(ios::fixed | ios::showpoint);
    cout.precision(5);
// interpolation for point u
    u = -0.33;

// print arrays of x and y for interpolation
    i=0;
    cout << " original array for interpolation " << endl;
    cout << setw(5) << "point" << setw(12) << "x" << setw(12) << "y" << endl;
    while (i <= n-1)
    {
        cout << setw(5) << i << setw(12) << x[i] << setw(12) << y[i] << endl;
        i = i+1;

     }

// call spline to calculate spline coeficients
    spline (x, y, b, c, d, n);

// print spline coefficients (for curiosity)
    cout << endl << " spline coefficients for a curious mind" << endl;
    cout << setw(5) << "point" << setw(12) << "b" << setw(12) << "c"
         << setw(12)<< "d" << endl;
    i = 0;
    while (i <= n-1)
    {
        cout << setw(5) << i << setw(12) << b[i] << setw(12) << c[i]
             << setw(12)<<  d[i] << endl;
        i = i+1;
    }

// call seval for spline interpolation using coefficients calculated by spline()
    s = seval(x, y, b, c, d, n, u);

// screen output
    cout << endl << " result of interpolation for point x " << endl;
    cout << endl << " x = " << u << " y = " << s << endl;
    system ("pause");
    return 0;
}

/* Test output 

 original array for interpolation
point           x           y
    0    -1.00000     0.03850
    1    -0.80000     0.05880
    2    -0.60000     0.10000
    3    -0.40000     0.20000
    4    -0.20000     0.50000
    5     0.00000     1.00000
    6     0.20000     0.50000
    7     0.40000     0.20000
    8     0.60000     0.10000
    9     0.80000     0.05880
   10     1.00000     0.03850

 spline coefficients for a curious mind
point           b           c           d
    0     0.11201    -0.21048     0.78958
    1     0.12257     0.26327     0.76938
    2     0.32020     0.72490     0.87041
    3     0.71461     1.24714    13.39898
    4     2.82135     9.28653   -54.46633
    5    -0.00000   -23.39327    54.46633
    6    -2.82135     9.28653   -13.39898
    7    -0.71461     1.24714    -0.87041
    8    -0.32020     0.72490    -0.76938
    9    -0.12257     0.26327    -0.78958
   10    -0.11201    -0.21048    -0.78958

 result of interpolation for point x

 x = -0.33000 y = 0.26073
 
*/